In general, lubricant oil, which is received in an oil filter for an internal combustion engine or a machining tool, becomes hot. Accordingly, a worker, who drains oil remaining in an oil filter, have to be restricted from getting burned and getting dirt with drained oil in a draining work when a filter element is replaced.
According to JP-A-11-104408, a pipe member 14 is provided in a filter body of a fluid filter, and a cylindrical drain plug 15f is screwed into the pipe member 14. The drain plug 15f axially extends to the outside of the filter body. The drain plug 15f has a window hole 15f. When the drain plug 15f is screwed into the pipe member 14, the window hole 15f is blocked with the sidewall of the pipe member 14. When the drain plug 15f is loosened, the window hole 15f is positioned on the lower side of the sidewall of the pipe member 14, so that the window hole 15f communicates with a gap formed between the pipe member 14 and the filter body. Thus, fluid remaining in the fluid filter flows into the window hole 15f of the drain plug 15f through the gap, so that the fluid is drained to the outside of the filter body through the drain plug 15. Fluid remaining in the filter body can be drained to a predetermined place using this drain structure. Therefore, drained oil can be restricted from dripping to a worker, so that the worker can be restricted from getting burned and getting dirt.
However, in this fluid filter, the window hole 15f of the drain plug 15f is received in the pipe member 14. Accordingly, the window hole 15f, i.e., drain port cannot be largely formed. When the window hole 15f is small, remaining fluid cannot be quickly drained. As a result, draining work and replacement of the filter element takes long. Generally, a vehicular engine oil filter is replaced by a professional worker in a service station. While the filter element is replaced, a vehicle owner has to wait, accordingly, a draining time needs to be shortened. Here, the drain port of remaining fluid, i.e., window hole 15f may be enlarged, however in this structure, the fluid filter may be jumboized.
According to JP-A-2004-160348, a drain structure, in which a drainpipe is detachable from a drain hole formed in a cap of a fluid filter, is disclosed. In this drain structure, when the drainpipe is inserted, a valve member blocking the drain hole can be unblocked, so that the drain hole can be communicated with a drain passage formed in the sidewall of the inserted drainpipe. Most of the sidewall of the inserted drainpipe is used as a drain port, so that the drain port can be enlarged without jumboizing the drainpipe, and draining work can be efficiently performed. However, in this fluid filter, gripping force supporting the drainpipe is small, because the sidewall of the drainpipe is used as the drain port. Besides, a supporting member cannot be provided to the sidewall, because an additional supporting member may reduce efficiency of draining. When gripping force is small, the drainpipe may be detached or the drainpipe may be inclined in draining work.
Besides, the fluid filter needs to be entirely or partially replaced in accordance with pollution of the filter element and deterioration of a seal member. Normally, the seal member, which restricts fluid from leaking to the outside, is replaced simultaneously with the filter element.
In replaceable type filters according to JP-A-11-104408 and JP-A-2004-160348, fluid remaining in the fluid filter can be drained using a pipe member before replaceable components such as a filter element and a seal member are replaced.
In a quickly replaceable throwaway type oil filter according to JP-U-58-26911, a fluid filter is entirely replaced as appropriate. This oil filter is provided to a filter mounting portion 9 of an internal combustion engine. A gasket 3 is provided between the oil filter and the filter mounting portion 9. The gasket 3 prevents oil in the oil filter from leaking. The gasket 3 is supported by a gasket holding plate 2, which can receive the gasket that includes an edge portion and a string portion in the lower inner peripheral portion of the gasket. The gasket is supported by the gasket holding plate 2 having a special shape, so that the gasket 3 is not dropped from the oil filter when the oil filter is removed from the filter mounting portion 9. Therefore, the gasket can be quickly removed simultaneously with removing the oil filter, so that draining process can be reduced. However, this special shaped gasket holding plate 2 is applicable to a throwaway type fluid filter, and is difficult to apply to a replaceable type filter. In the fluid filters disclosed in JP-A-11-104408 and JP-A-2004-160348, a seal member 15g needs to be replaced in addition to a replacing work of the filter element. Accordingly, total replacing work takes long, and replacing work becomes complicated.